2 Network Basics. types of communication service. how communication services are implemented. network performance measures. switching.

Size: px
Start display at page:

Download "2 Network Basics. types of communication service. how communication services are implemented. network performance measures. switching."

Transcription

1 2 Network Basics types of communication service how communication services are implemented switching multiplexing network performance measures 1

2 2.1 Types of service in a layered network architecture connection-oriented: establish a connection use the connection (for data transfer) release the connection modelled on the telephone system essential feature: sender pushes objects (e.g. bits, packets) in at one end of the connection, and receiver takes them out in the same order at the other end connectionless: each message is sent independently of any other messages going from the same sender to the same receiver modelled on the postal service essential features: each message must include the receiver s address, and messages can be received in a different order to the order in which they were transmitted 2

3 Types of service in a layered network architecture (cont.) each type of service can be characterised by its reliability: whether or not the service guarantees to correctly deliver the data a reliable service is typically implemented by having the receiver confirm to the sender that it correctly received each message (which introduces extra overhead and delays) reliable connection-oriented service has 2 variations: message stream:preserves message boundaries (e.g. 2 1-kB messages are received as 2 1-kB messages, not 1 2-kB message, byte messages, or anything else) byte stream: doesn t preserve message boundaries (e.g. 2 1-kB messages are received as a 2048-byte stream) unreliable connection-oriented service e.g. real-time audio or video: tolerates some errors or losses in transmission (quality decreases as errors/losses increase) 3

4 Types of service in a layered network architecture (cont.) connectionless service can be unreliable (no 100% delivery guarantee), acknowledged (receipt confirmed), or request-reply (a single short message contains a request, another the reply) 4

5 Types of service in a layered network architecture (cont.) Note: communication services are defined based on end-to-end properties, not on how bits are transported in the network a single network could offer more than one type of service e.g. the Internet supports all of them, more or less may have different implementations of the same service e.g. connection-oriented delivery of a voice bit stream can be implemented by packet voice or a dedicated circuit 5

6 2.2 How are communication services implemented? it is economically infeasible to directly connect every pair of sender-receiver pairs (e.g. mesh or star) in a large network technology limitations mean that broadcast solutions don t scale to large numbers of hosts or large geographical distances therefore network resources must be shared between the users, while still allowing senders to transmit data to their receivers the two basic techniques that permit connectivity while sharing resources are switching and multiplexing switching: sharing network resources among multiple transmissions multiplexing: sharing a single link among multiple transmissions 6

7 Circuit switching a path is set up in the network between the sender and the receiver (by making the appropriate connections in the switches) the necessary network resources are reserved for the connection prior to any data transfer; if this is not possible, the connection request is blocked these reserved resources are then held for the duration of the connection, regardless of actual usage Switch = a device that can create a temporary connection between an input link and an output link 7

8 Circuit switching (cont.) network links are not shared at the same time the links in a path are monopolised for the duration of the connection, then released so that they are available for other connections the connection set-up delay can be significant (>1 second) circuit switching is ideal for smooth network traffic e.g. telephone network what if the traffic from sender to receiver is bursty (which means it varies widely around its average value)? computer-to-computer traffic can be very bursty could set up a new circuit for each burst could hold original circuit for duration of data transfer both of these solutions are wasteful of network resources 8

9 Packet switching packet = string of bits (up to a few thousand, typically) uses store-and-forward operation: In packet switching, an upper limit is placed on packet size, and packet transmissions are pipelined (reducing the overall delay) circuit switching message switching packet switching 9

10 Packet switching (cont.) 2 basic types of packet switching: datagram vs. virtual circuit Datagram packet switching: each packet is treated individually within the network, so successive packets may follow different routes through it each packet contains the receiver s address and a sequence number (so that receiver can put them into correct order) Network nodes are routers, which have routing tables telling them which output link to use for each possible destination 10

11 Packet switching (cont.): Datagram packet switching no connection set-up needed flexible routing possible (e.g. if a router crashes) network resources are not shared at the same time each packet monopolises a link during its transmission, after which the link is available for other packet transmissions ideal for short-lived bursty traffic less suitable for long-lived &/or interactive bursty traffic 11

12 Packet switching (cont.) Virtual circuit packet switching: a route is set up in the network between sender and receiver (by making appropriate entries in the routing tables) resources may or may not be reserved for this route. If resources need to be reserved and are not available, the connection request is blocked each packet contains its virtual circuit identifier Routers have routing tables telling them which output link to use for each established virtual circuit 12

13 Packet switching (cont.): Virtual circuit packet switching connection set-up required, which may involve significant delay network resources are not shared at the same time each packet monopolises a link during its transmission, after which the link is available for other packet transmissions less work required at intermediate routers than for datagram p.s. given a packet s input link and virtual circuit identifier, the router can look up its routing table to find the output link virtual circuits not as robust to network problems as datagram p.s. 13

14 Packet switching (cont.): Comparison virtual circuit p.s. represents a compromise between circuit switching and datagram p.s. circuit switching creates a path in the network; virtual circuit p.s. creates a route which exists only in software; datagram p.s. doesn t have routes in circuit switching, the links in the path cannot be shared during the connection; in virtual circuit and datagram p.s. they can 14

15 2.2.2 Multiplexing sharing a single link among multiple transmissions 3 basic possibilities: Frequency division multiplexing (FDM) Time division multiplexing (TDM) Statistical multiplexing 15

16 Multiplexing: Frequency Division Multiplexing (FDM) 16

17 Multiplexing: Time Division Multiplexing (TDM) 17

18 Multiplexing: Statistical Multiplexing both FDM and TDM divide the link into independent channels inefficient if traffic is bursty, since no sharing allowed in statistical multiplexing, the idea is that the link should never be idle when there is data to be transferred Frames have an additional overhead (compared to FDM or TDM) to indicate which input stream they belong to; the packet queueing delay is now variable; and a (possibly complex) method is needed to decide which packets to multiplex 18

19 Transmission Modes Simplex Half-duplex Full-duplex 19

20 2.3 Network Performance Measures l = length of signal path in communication medium (metres) v = signal propagation speed in the medium (metres/second) L = average length of frame or packet (bits) C = transmission rate (bits/second) Propagation delay = l / v, in seconds shows how long a bit takes to propagate along the path Transmission time = L / C, in seconds shows how long it takes to get packet onto the medium Throughput: how fast data can pass a certain point can be measured in bits/second, packets/second, Efficiency is related to throughput, e.g. efficiency = throughput (in packets/sec) * packet transmission time 20

21 Network performance measures: Example 1 Consider an optical fibre 3000 km long with a transmitter transmitting at 1.5 Gbps (1 Gbps = bps). The signal propagation speed in optical fibre is approximately km/sec. Suppose packet switching is being used with a packet length of 2000 bits. What is the bit propagation delay along the fibre? prop_delay = ( )/( ) = 15 millisec What is the packet transmission time here? pkt_trans = (2 000)/( ) = microsec How many packets have been transmitted and are propagating over the fibre when the first bit reaches the destination? num_pkts = ( )/( ) = packets (Note that this is bits) 21

22 Network performance measures: Example 2 Consider a route in a store-and-forward network going through 8 intermediate nodes. The packets contain 1000 bits and are transmitted at 64 kbps. Assume propagation delays over the links are negligible. As a packet travels along the route, it encounters an average of 5 packets when it arrives at each node. How long does it take for the packet to get to the receiver if the nodes transmit on a first come first served basis? At each intermediate node, 6 packets must be transmitted in order for our packet to be transmitted: our packet finds 5 packets ahead of it, which will be transmitted first due to the first come first served policy. The packet transmission time at every node is pkt_trans = (1 000)/(64 000) = millisec The total travel time for our packet through the network is travel_time = (transmission delay at sender) + 8 (delay at each intermediate node) = pkt_trans pkt_trans = 766 millisec 22

23 Network performance measures: Example 2 (cont.) Note that the pure transmission delays only account for route_trans = pkt_trans + 8 pkt_trans = 141 millisec Our packet endures a queueing node of delay in each intermediate node_q_delay = 5 pkt_trans = 78 millisec and since there are 8 intermediate nodes, the total queueing delay along this route is route_q_delay = 8 node_q_delay = 625 millisec which represents just over 80% of the total travel time. Queueing delay can account for a substantial extra delay experienced by packets in the network One way to reduce this queueing delay FOR SOME PACKETS would be to use a different policy in the intermediate nodes, rather than first-come-first-served. This could result in some higher-priority packets getting to their receivers much quicker, while lower-priority packets would experience longer delays. 23

24 Network performance measures: Example nodes are connected to a 1000 metre length of coaxial cable. Using some (unspecified) protocol, each node can transmit 70 frames/second, where each frame is 1000 bits long. The transmission rate at each node is 100 Mbps. What is the per-node throughput? thru_node = = bps What is the total throughput (of the 150 nodes)? thru_total = 150 thru_node = bps = 10.5 Mbps What is the efficiency of this protocol? efficiency = (total throughput, in bps) (bit transmission time) = ( ) (1/ ) = 0.105, or 10.5% OR efficiency = (total throughput, in frames per second) (frame transmission time) = (70 150) (1 000/ ) = 0.105, or 10.5% 24

25 Network performance measures: Example 3 (cont.) What would give us 100% efficiency, and why is the efficiency so far below 100% here? If some node in the network was transmitting at every instant of time, the total throughput would be 100 Mbps and the efficiency would be 100%. However, the protocol being used to regulate access to the medium (the coaxial cable) introduces some delays between transmissions either because it permits collisions to occur, which must be recovered from; or because some permission to transmit token must be passed from the node currently in possession to the next node allowed by the protocol to transmit. In either case, these inter-transmission gaps result in a drop in efficiency. Note that, although this efficiency seems low, it may be perfectly acceptable. For example, if the objective was to run the network with a minimum throughput of 10 Mbps, this protocol works OK. 25

A closer look at network structure:

A closer look at network structure: T1: Introduction 1.1 What is computer network? Examples of computer network The Internet Network structure: edge and core 1.2 Why computer networks 1.3 The way networks work 1.4 Performance metrics: Delay,

More information

Internet Architecture and Protocol

Internet Architecture and Protocol Internet Architecture and Protocol Set# 04 Wide Area Networks Delivered By: Engr Tahir Niazi Wide Area Network Basics Cover large geographical area Network of Networks WANs used to be characterized with

More information

Outline: Connecting Many Computers

Outline: Connecting Many Computers Outline: Connecting Many Computers Last lecture: sending data between two computers This lecture: link-level network protocols (from last lecture) sending data among many computers 1 Review: A simple point-to-point

More information

Lecture 2 Communication services The Trasport Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it

Lecture 2 Communication services The Trasport Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Lecture 2 Communication services The Trasport Layer Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it The structure edge: applications and hosts core: routers of s access s, media:

More information

Wireless Networks. Communication Networks

Wireless Networks. Communication Networks Wireless Networks Communication Networks Types of Communication Networks Traditional Traditional local area network (LAN) Traditional wide area network (WAN) Higher-speed High-speed local area network

More information

QUESTION 1 QUESTION 2 QUESTION 3 QUESTION 4 QUESTION 5 QUESTION 6

QUESTION 1 QUESTION 2 QUESTION 3 QUESTION 4 QUESTION 5 QUESTION 6 QUESTION 1 Three packet-switching networks each contain 8 nodes, A - H. The first network has a star topology with a central switch; the second is a (bidirectional) ring; and the third is a fully interconnected

More information

Computer Communication Networks

Computer Communication Networks Contents ELL 785 Computer Communication Networks Introduction Lecture 1 Taxonomy of communication works Computer Communication Networks Building a work ed work architecture 1-1 Introduction PC server wireless

More information

Communication and Networks. Problems

Communication and Networks. Problems Electrical and Information Technology Communication and Networks Problems Link Layer 2016 Problems 1. Consider a network applying a slotted Aloha access system. The assumption for this is that all nodes

More information

Islamic University of Gaza Faculty of Engineering Department of Computer Engineering ECOM 4021: Networks Discussion. Chapter 1.

Islamic University of Gaza Faculty of Engineering Department of Computer Engineering ECOM 4021: Networks Discussion. Chapter 1. Islamic University of Gaza Faculty of Engineering Department of Computer Engineering ECOM 4021: Networks Discussion Chapter 1 Foundation Eng. Haneen El-Masry February, 2014 A Computer Network A computer

More information

INTRODUCTORY COMPUTER

INTRODUCTORY COMPUTER INTRODUCTORY COMPUTER NETWORKS TYPES OF NETWORKS Faramarz Hendessi Introductory Computer Networks Lecture 4 Fall 2010 Isfahan University of technology Dr. Faramarz Hendessi 2 Types of Networks Circuit

More information

COM-208: Computer Networks - Homework 1

COM-208: Computer Networks - Homework 1 COM-208: Computer Networks - Homework 1 1. Design an application-level protocol to be used between an TM (automatic teller machine) and a bank s centralized server. The protocol should allow: verifying

More information

CSE3213 Computer Network I

CSE3213 Computer Network I CSE3213 Computer Network I Introduction Course page: http://www.cse.yorku.ca/course/3213 1 Course Contents 3 general areas: data communications, networking, and protocols 1. Data communications: basic

More information

EEC-484/584 Computer Networks

EEC-484/584 Computer Networks EEC-484/584 Computer Networks Lecture 2 Wenbing Zhao wenbing@ieee.org (Lecture nodes are based on materials supplied by Dr. Louise Moser at UCSB and Prentice-Hall) Misc. Interested in research? Secure

More information

Lecture 4. Data Transmission Modes and Switching. Data Transmission & Switching 1-1

Lecture 4. Data Transmission Modes and Switching. Data Transmission & Switching 1-1 Lecture 4 Data Transmission Modes and Switching Data Transmission & Switching 1-1 Agenda Introduction to Data Transmission Modes Parallel and Serial Transmission Transmission Media Guided and unguided

More information

UNIT- 2 Physical Layer and Overview of PL Switching

UNIT- 2 Physical Layer and Overview of PL Switching UNIT- 2 Physical Layer and Overview of PL Switching 2.1 MULTIPLEXING Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link. Figure

More information

CS 5520/ECE 5590NA: Network Architecture I Spring Lecture 13: UDP and TCP

CS 5520/ECE 5590NA: Network Architecture I Spring Lecture 13: UDP and TCP CS 5520/ECE 5590NA: Network Architecture I Spring 2008 Lecture 13: UDP and TCP Most recent lectures discussed mechanisms to make better use of the IP address space, Internet control messages, and layering

More information

Communication Networks

Communication Networks Communication Networks Chapter 3 Multiplexing Frequency Division Multiplexing (FDM) Useful bandwidth of medium exceeds required bandwidth of channel Each signal is modulated to a different carrier frequency

More information

TCOM 370 NOTES 99-1 NETWORKING AND COMMUNICATIONS

TCOM 370 NOTES 99-1 NETWORKING AND COMMUNICATIONS TCOM 370 NOTES 99-1 NETWORKING AND COMMUNICATIONS Communication Networks Allow Exchange of Information between Users telephone network for voice communication interconnected computers and peripherals,

More information

BROADBAND AND HIGH SPEED NETWORKS

BROADBAND AND HIGH SPEED NETWORKS BROADBAND AND HIGH SPEED NETWORKS SWITCHING A switch is a mechanism that allows us to interconnect links to form a larger network. A switch is a multi-input, multi-output device, which transfers packets

More information

Computer Networks and the Internet. CMPS 4750/6750: Computer Networks

Computer Networks and the Internet. CMPS 4750/6750: Computer Networks Computer Networks and the Inter CMPS 4750/6750: Computer Networks Outline What Is the Inter? Access Networks Packet Switching and Circuit Switching A closer look at delay, loss, and throughput Interconnection

More information

Physical Layer: Multiplexing, Spectrum Spreading and Switching. Covers Chapters# 06 & 08 from Text Book

Physical Layer: Multiplexing, Spectrum Spreading and Switching. Covers Chapters# 06 & 08 from Text Book Physical Layer: Multiplexing, Spectrum Spreading and Switching Covers Chapters# 06 & 08 from Text Book 2 Multiplexing From Chapter#06 3 Multiplexing If bandwidth of a medium linking two devices is greater

More information

Data Networks. Lecture 1: Introduction. September 4, 2008

Data Networks. Lecture 1: Introduction. September 4, 2008 Data Networks Lecture 1: Introduction September 4, 2008 Slide 1 Learning Objectives Fundamental aspects of network Design and Analysis: Architecture: layering, topology design, switching mechanisms Protocols:

More information

2. Traffic lect02.ppt S Introduction to Teletraffic Theory Spring

2. Traffic lect02.ppt S Introduction to Teletraffic Theory Spring lect02.ppt S-38.145 - Introduction to Teletraffic Theory Spring 2005 1 Contents Traffic characterisation Telephone traffic modelling Data traffic modelling at packet level Data traffic modelling at flow

More information

Topics. Link Layer Services (more) Link Layer Services LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS. flow control: error detection:

Topics. Link Layer Services (more) Link Layer Services LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS. flow control: error detection: 1 Topics 2 LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS Multiple access: CSMA/CD, CSMA/CA, token passing, channelization LAN: characteristics, i basic principles i Protocol architecture Topologies

More information

2. Modelling of telecommunication systems (part 1)

2. Modelling of telecommunication systems (part 1) 2. Modelling of telecommunication systems (part ) lect02.ppt S-38.45 - Introduction to Teletraffic Theory - Fall 999 2. Modelling of telecommunication systems (part ) Contents Telecommunication networks

More information

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols Link Layer: Introduction daptors ommunicating hosts and routers are nodes links connect nodes wired links wireless links layer-2 packet is a frame, encapsulates datagram datagram controller sending host

More information

Chapter 10. Circuits Switching and Packet Switching 10-1

Chapter 10. Circuits Switching and Packet Switching 10-1 Chapter 10 Circuits Switching and Packet Switching 10-1 Content Switched communication networks Circuit switching networks Circuit-switching concepts Packet-switching principles X.25 (mentioned but not

More information

Module 2 Overview of Computer Networks

Module 2 Overview of Computer Networks Module 2 Overview of Computer Networks Networks and Communication Give me names of all employees Who earn more than $00,000 ISP intranet backbone satellite link desktop computer: server: network link:

More information

Module 2 Overview of. Computer Networks

Module 2 Overview of. Computer Networks Module Overview of Networks and Communication Give me names of all employees Who earn more than $00,000 ISP intranet backbone satellite link desktop computer: server: network link: CS454/654 - Issues How

More information

end systems, access networks, links circuit switching, packet switching, network structure

end systems, access networks, links circuit switching, packet switching, network structure Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge end systems, access networks, links 1.3 Network core circuit switching, packet switching, network structure 1.4 Delay, loss and throughput

More information

CCM 4300 Lecture 5 Computer Networks, Wireless and Mobile Communications. Dr Shahedur Rahman. Room: T115

CCM 4300 Lecture 5 Computer Networks, Wireless and Mobile Communications. Dr Shahedur Rahman. Room: T115 CCM 4300 Lecture 5 Computer Networks, Wireless and Mobile Communications Dr Shahedur Rahman s.rahman@mdx.ac.uk Room: T115 1 Recap of Last Session Described the physical layer Analogue and Digital signal

More information

Switching CHAPTER 8. Solutions to Review Questions and Exercises. Review Questions

Switching CHAPTER 8. Solutions to Review Questions and Exercises. Review Questions CHAPTER 8 Switching Solutions to Review Questions and Exercises Review Questions 1. Switching provides a practical solution to the problem of connecting multiple devices in a network. It is more practical

More information

JAMES F. KUROSE AND KEITH W. ROSS

JAMES F. KUROSE AND KEITH W. ROSS JAMES F. KUROSE AND KEITH W. ROSS What is the internet? There is no one definition. Two ways to try to describe it: Nuts and bolts i.e. the basic hardware and software components A networking infrastructure

More information

UNIT-II OVERVIEW OF PHYSICAL LAYER SWITCHING & MULTIPLEXING

UNIT-II OVERVIEW OF PHYSICAL LAYER SWITCHING & MULTIPLEXING 1 UNIT-II OVERVIEW OF PHYSICAL LAYER SWITCHING & MULTIPLEXING Syllabus: Physical layer and overview of PL Switching: Multiplexing: frequency division multiplexing, wave length division multiplexing, synchronous

More information

2. Traffic. Contents. Offered vs. carried traffic. Characterisation of carried traffic

2. Traffic. Contents. Offered vs. carried traffic. Characterisation of carried traffic Contents characterisation Telephone traffic modelling Data traffic modelling at packet level Data traffic modelling at flow level lect.ppt S-8.5 - Introduction to Teletraffic Theory Spring 6 Offered vs.

More information

Wide area networks: packet switching and congestion

Wide area networks: packet switching and congestion Wide area networks: packet switching and congestion Packet switching ATM and Frame Relay Congestion Circuit and Packet Switching Circuit switching designed for voice Resources dedicated to a particular

More information

Local Area Networks (LANs): Packets, Frames and Technologies Gail Hopkins. Part 3: Packet Switching and. Network Technologies.

Local Area Networks (LANs): Packets, Frames and Technologies Gail Hopkins. Part 3: Packet Switching and. Network Technologies. Part 3: Packet Switching and Gail Hopkins Local Area Networks (LANs): Packets, Frames and Technologies Gail Hopkins Introduction Circuit Switching vs. Packet Switching LANs and shared media Star, bus and

More information

Digital Communication Networks

Digital Communication Networks Digital Communication Networks MIT PROFESSIONAL INSTITUTE, 6.20s July 25-29, 2005 Professor Muriel Medard, MIT Professor, MIT Slide 1 Digital Communication Networks Introduction Slide 2 Course syllabus

More information

CS 344/444 Computer Network Fundamentals Final Exam Solutions Spring 2007

CS 344/444 Computer Network Fundamentals Final Exam Solutions Spring 2007 CS 344/444 Computer Network Fundamentals Final Exam Solutions Spring 2007 Question 344 Points 444 Points Score 1 10 10 2 10 10 3 20 20 4 20 10 5 20 20 6 20 10 7-20 Total: 100 100 Instructions: 1. Question

More information

Data Link Layer. Our goals: understand principles behind data link layer services: instantiation and implementation of various link layer technologies

Data Link Layer. Our goals: understand principles behind data link layer services: instantiation and implementation of various link layer technologies Data Link Layer Our goals: understand principles behind data link layer services: link layer addressing instantiation and implementation of various link layer technologies 1 Outline Introduction and services

More information

Introductions. Computer Networking Lecture 01. January 16, HKU SPACE Community College. HKU SPACE CC CN Lecture 01 1/36

Introductions. Computer Networking Lecture 01. January 16, HKU SPACE Community College. HKU SPACE CC CN Lecture 01 1/36 Introductions Computer Networking Lecture 01 HKU SPACE Community College January 16, 2012 HKU SPACE CC CN Lecture 01 1/36 Outline What is a Computer Network? Basic Requirements of Building a Computer Network

More information

Layer 3: Network Layer. 9. Mar INF-3190: Switching and Routing

Layer 3: Network Layer. 9. Mar INF-3190: Switching and Routing Layer 3: Network Layer 9. Mar. 2005 1 INF-3190: Switching and Routing Network Layer Goal Enable data transfer from end system to end system End systems Several hops, (heterogeneous) subnetworks Compensate

More information

COPYRIGHTED MATERIAL INTRODUCTION AND OVERVIEW

COPYRIGHTED MATERIAL INTRODUCTION AND OVERVIEW 1 INTRODUCTION AND OVERVIEW The past few decades have seen the merging of computer and communication technologies Wide-area and local-area computer networks have been deployed to interconnect computers

More information

end systems, access networks, links 1.3 network core

end systems, access networks, links 1.3 network core Chapter 1: roadmap 1.1 what is the Inter? 1.2 work edge end systems, works, links 1.3 work core packet switching, circuit switching, work structure 1.4 delay, loss, throughput in works 1.5 protocol layers,

More information

Lecture #6 Multiplexing and Switching

Lecture #6 Multiplexing and Switching SPRING 2015 Integrated Technical Education Cluster At AlAmeeria E-626-A Data Communication and Industrial Networks (DC-IN) Lecture #6 Multiplexing and Switching Instructor: Dr. Ahmad El-Banna 1 Agenda

More information

CS321: Computer Networks Introduction to Computer Networks and Internet

CS321: Computer Networks Introduction to Computer Networks and Internet CS321: Computer Networks Introduction to Computer Networks and Internet Dr. Manas Khatua Assistant Professor Dept. of CSE IIT Jodhpur E-mail: manaskhatua@iitj.ac.in What is Data Communication? Data communications

More information

Next Steps Spring 2011 Lecture #18. Multi-hop Networks. Network Reliability. Have: digital point-to-point. Want: many interconnected points

Next Steps Spring 2011 Lecture #18. Multi-hop Networks. Network Reliability. Have: digital point-to-point. Want: many interconnected points Next Steps Have: digital point-to-point We ve worked on link signaling, reliability, sharing Want: many interconnected points 6.02 Spring 2011 Lecture #18 multi-hop networks: design criteria network topologies

More information

Review of Network Technologies

Review of Network Technologies Indian Institute of Technology Kharagpur Review of Network Technologies Prof. Indranil Sen Gupta Dept. of Computer Science & Engg. I.I.T. Kharagpur, INDIA Lecture 2: Review of network technologies On completion,

More information

CS 457 Networking and the Internet. Network Overview (cont d) 8/29/16. Circuit Switching (e.g., Phone Network) Fall 2016 Indrajit Ray

CS 457 Networking and the Internet. Network Overview (cont d) 8/29/16. Circuit Switching (e.g., Phone Network) Fall 2016 Indrajit Ray 8/9/6 CS 457 Networking and the Internet Fall 06 Indrajit Ray Network Overview (cont d) Circuit vs. Packet Switching Best Effort Internet Model Circuit Switching (e.g., Phone Network) Step : Source establishes

More information

CN1047 INTRODUCTION TO COMPUTER NETWORKING CHAPTER 6 OSI MODEL TRANSPORT LAYER

CN1047 INTRODUCTION TO COMPUTER NETWORKING CHAPTER 6 OSI MODEL TRANSPORT LAYER CN1047 INTRODUCTION TO COMPUTER NETWORKING CHAPTER 6 OSI MODEL TRANSPORT LAYER Transport Layer The Transport layer ensures the reliable arrival of messages and provides error checking mechanisms and data

More information

Reminder: Datalink Functions Computer Networking. Datalink Architectures

Reminder: Datalink Functions Computer Networking. Datalink Architectures Reminder: Datalink Functions 15-441 15 441 15-641 Computer Networking Lecture 5 Media Access Control Peter Steenkiste Fall 2015 www.cs.cmu.edu/~prs/15-441-f15 Framing: encapsulating a network layer datagram

More information

WAN Technologies CCNA 4

WAN Technologies CCNA 4 WAN Technologies CCNA 4 Overview Note: Most of this will be described in more detail in later chapters. Differentiate between a LAN and WAN Identify the devices used in a WAN List WAN standards Describe

More information

Outline. Computer Communication and Networks. The Network Core. Components of the Internet. The Network Core Packet Switching Circuit Switching

Outline. Computer Communication and Networks. The Network Core. Components of the Internet. The Network Core Packet Switching Circuit Switching Outline Computer Communication and Networks 1 Department of Computer Science & Information Technology University of Balochistan Lecture 03 1/26 2/26 Two major components The mesh of packet switches and

More information

Department of Computer and IT Engineering University of Kurdistan. Data Communication Netwotks (Graduate level) Data Link Layer

Department of Computer and IT Engineering University of Kurdistan. Data Communication Netwotks (Graduate level) Data Link Layer Department of Computer and IT Engineering University of Kurdistan Data Communication Netwotks (Graduate level) Data Link Layer By: Dr. Alireza Abdollahpouri Data Link Layer 2 Data Link Layer Application

More information

Announcements. TAs office hours: Mohamed Grissa: Mohamed Alkalbani:

Announcements. TAs office hours: Mohamed Grissa: Mohamed Alkalbani: Announcements TAs office hours: Mohamed Grissa: grissam@oregonstate.edu Tuesday: 4-5 Friday: 11-12 Mohamed Alkalbani: alkalbmo@oregonstate.edu Wednesday: 11-12 Thursday: 11-12 Lecture slides: Will be posted

More information

Chapter 6 Questions. Problems

Chapter 6 Questions. Problems Chapter 6 Questions Q6-1. Q6-2. Q6-3. Q6-4. Q6-5. Q6-6. Q6-7. Describe the goals of multiplexing. List three main multiplexing techniques mentioned in this chapter. Distinguish between a link and a channel

More information

Basics of datacommunication

Basics of datacommunication Data communication I Lecture 1 Course Introduction About the course Basics of datacommunication How is information transported between digital devices? Essential data communication protocols Insight into

More information

Revision of Previous Lectures

Revision of Previous Lectures Lecture 15 Overview Last Lecture Local area networking This Lecture Wide area networking 1 Source: chapters 8.1-8.3, 17.1, 18.1, 18.2 Next Lecture Wide area networking 2 Source: Chapter 20 COSC244 Lecture

More information

Priority Traffic CSCD 433/533. Advanced Networks Spring Lecture 21 Congestion Control and Queuing Strategies

Priority Traffic CSCD 433/533. Advanced Networks Spring Lecture 21 Congestion Control and Queuing Strategies CSCD 433/533 Priority Traffic Advanced Networks Spring 2016 Lecture 21 Congestion Control and Queuing Strategies 1 Topics Congestion Control and Resource Allocation Flows Types of Mechanisms Evaluation

More information

Internet Architecture & Performance. What s the Internet: nuts and bolts view

Internet Architecture & Performance. What s the Internet: nuts and bolts view Internet Architecture & Performance Internet, Connection, Protocols, Performance measurements What s the Internet: nuts and bolts view millions of connected computing devices: hosts, end systems pc s workstations,

More information

Introduction to computer networking

Introduction to computer networking edge core Introduction to computer networking Comp Sci 3600 Security Outline edge core 1 2 edge 3 core 4 5 6 The edge core Outline edge core 1 2 edge 3 core 4 5 6 edge core Billions of connected computing

More information

This Lecture. BUS Computer Facilities Network Management. Switching Network. Simple Switching Network

This Lecture. BUS Computer Facilities Network Management. Switching Network. Simple Switching Network This Lecture BUS0 - Computer Facilities Network Management Switching networks Circuit switching Packet switching gram approach Virtual circuit approach Routing in switching networks Faculty of Information

More information

More on IO: The Universal Serial Bus (USB)

More on IO: The Universal Serial Bus (USB) ecture 37 Computer Science 61C Spring 2017 April 21st, 2017 More on IO: The Universal Serial Bus (USB) 1 Administrivia Project 5 is: USB Programming (read from a mouse) Optional (helps you to catch up

More information

ECE 650 Systems Programming & Engineering. Spring 2018

ECE 650 Systems Programming & Engineering. Spring 2018 ECE 650 Systems Programming & Engineering Spring 2018 Networking Introduction Tyler Bletsch Duke University Slides are adapted from Brian Rogers (Duke) Computer Networking A background of important areas

More information

Homework 1. Question 1 - Layering. CSCI 1680 Computer Networks Fonseca

Homework 1. Question 1 - Layering. CSCI 1680 Computer Networks Fonseca CSCI 1680 Computer Networks Fonseca Homework 1 Due: 27 September 2012, 4pm Question 1 - Layering a. Why are networked systems layered? What are the advantages of layering? Are there any disadvantages?

More information

Computer Networks. ENGG st Semester, 2010 Hayden Kwok-Hay So

Computer Networks. ENGG st Semester, 2010 Hayden Kwok-Hay So Computer Networks ENGG1015 1 st Semester, 2010 Hayden Kwok-Hay So Where are we in the semester? High Level Applications Systems Digital Logic Image & Video Processing Computer & Embedded Systems Computer

More information

CSC 401 Data and Computer Communications Networks

CSC 401 Data and Computer Communications Networks CSC 401 Data and Computer Communications Networks Computer Networks and The Inter Sec 1.3 Prof. Lina Battestilli Fall 2017 Outline Computer Networks and the Inter (Ch 1) 1.1 What is the Inter? 1.2 work

More information

IP Packet Switching. Goals of Todayʼs Lecture. Simple Network: Nodes and a Link. Connectivity Links and nodes Circuit switching Packet switching

IP Packet Switching. Goals of Todayʼs Lecture. Simple Network: Nodes and a Link. Connectivity Links and nodes Circuit switching Packet switching IP Packet Switching CS 375: Computer Networks Dr. Thomas C. Bressoud Goals of Todayʼs Lecture Connectivity Links and nodes Circuit switching Packet switching IP service model Best-effort packet delivery

More information

CMPE150 Midterm Solutions

CMPE150 Midterm Solutions CMPE150 Midterm Solutions Question 1 Packet switching and circuit switching: (a) Is the Internet a packet switching or circuit switching network? Justify your answer. The Internet is a packet switching

More information

Review of Topology and Access Techniques / Switching Concepts

Review of Topology and Access Techniques / Switching Concepts Review of Topology and s / Concepts BSAD 141 Dave Novak Sources: Network+ Guide to Networks, Dean 2013 Overview Three base wired topologies Bus, star, ring Two wireless topologies Ad-hoc, infrastructure

More information

NWEN 243. Networked Applications. Layer 4 TCP and UDP

NWEN 243. Networked Applications. Layer 4 TCP and UDP NWEN 243 Networked Applications Layer 4 TCP and UDP 1 About the second lecturer Aaron Chen Office: AM405 Phone: 463 5114 Email: aaron.chen@ecs.vuw.ac.nz Transport layer and application layer protocols

More information

Principles behind data link layer services

Principles behind data link layer services Data link layer Goals: Principles behind data link layer services Error detection, correction Sharing a broadcast channel: Multiple access Link layer addressing Reliable data transfer, flow control: Done!

More information

CHAPTER 3 EFFECTIVE ADMISSION CONTROL MECHANISM IN WIRELESS MESH NETWORKS

CHAPTER 3 EFFECTIVE ADMISSION CONTROL MECHANISM IN WIRELESS MESH NETWORKS 28 CHAPTER 3 EFFECTIVE ADMISSION CONTROL MECHANISM IN WIRELESS MESH NETWORKS Introduction Measurement-based scheme, that constantly monitors the network, will incorporate the current network state in the

More information

PLEASE READ CAREFULLY BEFORE YOU START

PLEASE READ CAREFULLY BEFORE YOU START Page 1 of 11 MIDTERM EXAMINATION #1 OCT. 13, 2011 COMPUTER NETWORKS : 03-60-367-01 U N I V E R S I T Y O F W I N D S O R S C H O O L O F C O M P U T E R S C I E N C E Fall 2011-75 minutes This examination

More information

Jaringan Komputer. Broadcast Network. Outline. MAC (Medium Access Control) Channel Allocation Problem. Dynamic Channel Allocation

Jaringan Komputer. Broadcast Network. Outline. MAC (Medium Access Control) Channel Allocation Problem. Dynamic Channel Allocation Broadcast Network Jaringan Komputer Medium Access Control Sublayer 2 network categories: point-to-point connections broadcast channels Key issue in broadcast network: how to determine who gets to use the

More information

Module 15: Network Structures

Module 15: Network Structures Module 15: Network Structures Background Topology Network Types Communication Communication Protocol Robustness Design Strategies 15.1 A Distributed System 15.2 Motivation Resource sharing sharing and

More information

Data and Computer Communications. Chapter 2 Protocol Architecture, TCP/IP, and Internet-Based Applications

Data and Computer Communications. Chapter 2 Protocol Architecture, TCP/IP, and Internet-Based Applications Data and Computer Communications Chapter 2 Protocol Architecture, TCP/IP, and Internet-Based s 1 Need For Protocol Architecture data exchange can involve complex procedures better if task broken into subtasks

More information

Chapter 15 Local Area Network Overview

Chapter 15 Local Area Network Overview Chapter 15 Local Area Network Overview LAN Topologies Bus and Tree Bus: stations attach through tap to bus full duplex allows transmission and reception transmission propagates throughout medium heard

More information

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols Link Layer: Introduction daptors ommunicating Terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are links wired links wireless links LNs

More information

What Is Congestion? Effects of Congestion. Interaction of Queues. Chapter 12 Congestion in Data Networks. Effect of Congestion Control

What Is Congestion? Effects of Congestion. Interaction of Queues. Chapter 12 Congestion in Data Networks. Effect of Congestion Control Chapter 12 Congestion in Data Networks Effect of Congestion Control Ideal Performance Practical Performance Congestion Control Mechanisms Backpressure Choke Packet Implicit Congestion Signaling Explicit

More information

Introduction to Real-Time Communications. Real-Time and Embedded Systems (M) Lecture 15

Introduction to Real-Time Communications. Real-Time and Embedded Systems (M) Lecture 15 Introduction to Real-Time Communications Real-Time and Embedded Systems (M) Lecture 15 Lecture Outline Modelling real-time communications Traffic and network models Properties of networks Throughput, delay

More information

Networks 15.2 Multiplexing Technologies Access Networks 15.5 Common Peripheral Interfaces

Networks 15.2 Multiplexing Technologies Access Networks 15.5 Common Peripheral Interfaces Chapter 15 Computer and Multimedia Networks 15.11 Basics of Computer and Multimedia Networks 15.2 Multiplexing Technologies 15.3 LAN and WAN 15.4 Access Networks 15.5 Common Peripheral Interfaces 15.6

More information

Announcements. CS 5565 Network Architecture and Protocols. Outline for today. The Internet: nuts and bolts view. The Internet: nuts and bolts view

Announcements. CS 5565 Network Architecture and Protocols. Outline for today. The Internet: nuts and bolts view. The Internet: nuts and bolts view Announcements CS 5565 Network Architecture and Protocols Lecture 2 Godmar Back Created Lectures Page Created CS5565 Forum Use this to find a project partner All projects will be done in groups of up to

More information

Review. Error Detection: CRC Multiple access protocols. LAN addresses and ARP Ethernet. Slotted ALOHA CSMA/CD

Review. Error Detection: CRC Multiple access protocols. LAN addresses and ARP Ethernet. Slotted ALOHA CSMA/CD Review Error Detection: CRC Multiple access protocols Slotted ALOHA CSMA/CD LAN addresses and ARP Ethernet Some slides are in courtesy of J. Kurose and K. Ross Overview Ethernet Hubs, bridges, and switches

More information

PLEASE READ CAREFULLY BEFORE YOU START

PLEASE READ CAREFULLY BEFORE YOU START Page 1 of 20 MIDTERM EXAMINATION #1 - B COMPUTER NETWORKS : 03-60-367-01 U N I V E R S I T Y O F W I N D S O R S C H O O L O F C O M P U T E R S C I E N C E Fall 2008-75 minutes This examination document

More information

PLEASE READ CAREFULLY BEFORE YOU START

PLEASE READ CAREFULLY BEFORE YOU START Page 1 of 20 MIDTERM EXAMINATION #1 - A COMPUTER NETWORKS : 03-60-367-01 U N I V E R S I T Y O F W I N D S O R S C H O O L O F C O M P U T E R S C I E N C E Fall 2008-75 minutes This examination document

More information

ECE 650 Systems Programming & Engineering. Spring 2018

ECE 650 Systems Programming & Engineering. Spring 2018 ECE 650 Systems Programming & Engineering Spring 2018 Networking Transport Layer Tyler Bletsch Duke University Slides are adapted from Brian Rogers (Duke) TCP/IP Model 2 Transport Layer Problem solved:

More information

CSCD 433/533 Advanced Networks

CSCD 433/533 Advanced Networks CSCD 433/533 Advanced Networks Lecture 2 Network Review Winter 2017 Reading: Chapter 1 1 Topics Network Topics Some Review from CSCD330 Applications Common Services Architecture OSI Model AS and Routing

More information

Introduction. The fundamental purpose of data communications is to exchange information between user's computers, terminals and applications programs.

Introduction. The fundamental purpose of data communications is to exchange information between user's computers, terminals and applications programs. Introduction The fundamental purpose of data communications is to exchange information between user's computers, terminals and applications programs. Simplified Communications System Block Diagram Intro-1

More information

COMPUTER NETWORK Model Test Paper

COMPUTER NETWORK Model Test Paper Model Test Paper Question no. 1 is compulsory. Attempt all parts. Q1. Each question carries equal marks. (5*5 marks) A) Difference between Transmission Control Protocol (TCP) and User Datagram Protocol.

More information

Outline. Inter-Process Communication. IPC across machines: Problems. CSCI 4061 Introduction to Operating Systems

Outline. Inter-Process Communication. IPC across machines: Problems. CSCI 4061 Introduction to Operating Systems Outline CSCI 4061 Introduction to Operating Systems ing Overview Layering and Protocols TCP/IP Protocol Family Client-Server Model Instructor: Abhishek Chandra 2 Inter-Process Communication Intra-node:

More information

UNIT IV -- TRANSPORT LAYER

UNIT IV -- TRANSPORT LAYER UNIT IV -- TRANSPORT LAYER TABLE OF CONTENTS 4.1. Transport layer. 02 4.2. Reliable delivery service. 03 4.3. Congestion control. 05 4.4. Connection establishment.. 07 4.5. Flow control 09 4.6. Transmission

More information

Data & Computer Communication

Data & Computer Communication Basic Networking Concepts A network is a system of computers and other devices (such as printers and modems) that are connected in such a way that they can exchange data. A bridge is a device that connects

More information

Lecture 2: Internet Structure

Lecture 2: Internet Structure Lecture 2: Internet Structure COMP 332, Spring 2018 Victoria Manfredi Acknowledgements: materials adapted from Computer Networking: A Top Down Approach 7 th edition: 1996-2016, J.F Kurose and K.W. Ross,

More information

ET4254 Communications and Networking 1

ET4254 Communications and Networking 1 Topic 10:- Local Area Network Overview Aims:- LAN topologies and media LAN protocol architecture bridges, hubs, layer 2 & 3 switches 1 LAN Applications (1) personal computer LANs low cost limited data

More information

1/29/2008. From Signals to Packets. Lecture 6 Datalink Framing, Switching. Datalink Functions. Datalink Lectures. Character and Bit Stuffing.

1/29/2008. From Signals to Packets. Lecture 6 Datalink Framing, Switching. Datalink Functions. Datalink Lectures. Character and Bit Stuffing. /9/008 From Signals to Packets Lecture Datalink Framing, Switching Peter Steenkiste Departments of Computer Science and Electrical and Computer Engineering Carnegie Mellon University Analog Signal Digital

More information

Medium Access Protocols

Medium Access Protocols Medium Access Protocols Summary of MAC protocols What do you do with a shared media? Channel Partitioning, by time, frequency or code Time Division,Code Division, Frequency Division Random partitioning

More information

Introduction to Wireless Networking ECE 401WN Spring 2008

Introduction to Wireless Networking ECE 401WN Spring 2008 Introduction to Wireless Networking ECE 401WN Spring 2008 Lecture 2: Communication Networks The first major topic we will study will be WLANs. But before that, we need to consider a few basics of networking.

More information

CS 123: Lecture 12, LANs, and Ethernet. George Varghese. October 24, 2006

CS 123: Lecture 12, LANs, and Ethernet. George Varghese. October 24, 2006 CS 123: Lecture 12, LANs, and Ethernet George Varghese October 24, 2006 Selective Reject Modulus failure Example w = 2, Max = 3 0 0 1 3 0 A(1) A(2) 1 0 retransmit A(1) A(2) buffer Case 1 Case 2 reject

More information

Subject Data Communication. Subject Code 15CS46. Module 2 (Part 2) Multiplexing and Switching

Subject Data Communication. Subject Code 15CS46. Module 2 (Part 2) Multiplexing and Switching 1. What is multiplexing? What are types of multiplexing? (Dec 2012) Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link. If the

More information